Fast and Easy Disinfection of Coronavirus-Contaminated Face Masks Using Ozone Gas Produced by a Dielectric Barrier Discharge Plasma Generator.

During the COVID-19 pandemic, face masks have become limited in stock. Most of sterilization methods are not applicable for eliminating virus from face masks without compromising the filtration efficiency of the masks. In this study, using a human coronavirus (HCoV-229E) as a surrogate for SARS-CoV-2 contamination on KF94 face masks, we show that the virus loses its infectivity with a 4 log reduction when exposed for 10 s to 120 ppm ozone gas produced by a dielectric barrier discharge plasma generator. Scanning electron microscopy, particulate filtration efficiency (PFE), and inhalation resistance tests revealed that there was no detectable structural or functional deterioration observed in the electrocharged filter layer of Korea Filter (KF) 94 masks even after their excessive exposure to ozone. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) showed decreases in amplification efficiency of HCoV-229E RNA recovered from masks exposed to ozone, indicating the damage to the RNA by the ozone treatment. Our results demonstrate that the plasma generator rapidly disinfects contaminated face masks at least five times without compromising filtration efficiency.